I have one on my 240g right now for about 3 weeks. So far so good. It has a lot of media area and a lot of output. Be careful though, It is very large and I barely got mine in between my door in my stand. I had to shoehorn it in. I also have a Rena xp3 on the same tank and my water is crystal clear. To compare the two the Fluval fx5 has more media storage-bio and more output, but the xp3 is much easier to maintain and clean and is slightly quieter. I highly recommend either filter and Rena is coming out with the xp4 this summer, which should also be a winner. Good luck